September weather forecast
Grand Usine, French Guiana

The first month of the autumn, September, is still a hot month in Grand Usine, French Guiana, with an average temperature fluctuating between 34.1°C (93.4°F) and 20.5°C (68.9°F).

Temperature

The advent of September sees the average high-temperature at a still hot 34.1°C (93.4°F), subtly shifted from August's 32.8°C (91°F). From the heights of the September heat, Grand Usine records a mean nighttime low of 20.5°C (68.9°F).

Heat index

September's heat index is computed to be a burning hot 49°C (120.2°F). Warning: Heat cramps and heat exhaustion are anticipated. Heatstroke is a risk with ongoing activity.
Heat index determinations are made taking into account the shade and light air movements. Direct sunlight exposure may cause a 15 Fahrenheit (8 Celsius) degrees rise in the heat index.
Note: The heat index, also known as 'apparent temperature' or 'feels like', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. The experience of temperature can be subjective, varying based on the individual's activity and heat perception, influenced by factors like wind, attire, and metabolic variations. You should know that direct sun exposure can heighten weather effects, potentially elevating the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Youngsters are usually more at risk than adults, considering they sweat less. Additionally, their high skin surface area compared to their little bodies and their high heat production due to activity increases their risk.
The body's natural response to excessive warmth is perspiration, as it allows for cooling through sweat evaporation. In circumstances of high air temperature and humidity (high heat index), the body's perspiration is restricted, heightening the feeling of warmth. When the heat gained surpasses the body's cooling capacity, temperatures rise, signaling potential health concerns.

Humidity

In September, the average relative humidity in Grand Usine is 74%.

Rainfall

In Grand Usine, in September, during 14.3 rainfall days, 36mm (1.42") of precipitation is typically accumulated. Throughout the year, in Grand Usine, French Guiana, there are 265.5 rainfall days, and 1078mm (42.44") of precipitation is accumulated.

Daylight

In September, the average length of the day in Grand Usine is 12h and 8min.
On the first day of the month, sunrise is at 06:26 and sunset at 18:36. On the last day of September, sunrise is at 06:18 and sunset at 18:24 -03.

Sunshine

September and October, with an average of 8.8h of sunshine, are months with the most sunshine.

UV index

The months with the highest UV index are August through November, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV rays for average individuals.
Note: A daily high UV index of 7 in September leads to these guidelines:
Resist extreme sun exposure. Guarding against solar damage is essential. Avoid direct Sun exposure and seek shade from 10 a.m. to 4 p.m., the period of highest UV radiation. Remember, however, that not all shade structures offer full protection. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.